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Effects of plateau pikas on restoring succession of degraded grassland and plant community structure

LIU Wei,YAN Hongyu,WANG Xi,WANG Changting   

  • Online:2014-02-21 Published:2014-02-21

高原鼠兔对退化草地植物群落结构及恢复演替的影响

刘伟 严红宇 王溪 王长庭   

  1. 中国科学院西北高原生物研究所

Abstract: We analyzed plant community structure,species composition and aboveground biomass in areas with pika disturbance (control)and in areas were pikas were absent by enclosure and removal methods during 2009 -2011. The aim is to explain that effects of the plateau pika on restoring succession of degraded grassland and plant community structure. The
results showed that the mean heights and coverage of plant communities increased year by year,and reached their peaks in 2011 in removal treatments and controls,with mean heights of 6.5 cm,4.2 cm,respectively,that were significantly different between the removal treatments and control. Coverages were 126.5% ,117. 9% respectively,which were not significantly different. The aboveground biomass of grasses increased significantly by 1 965. 1% in removal treatments compared to controls. The aboveground biomass of sedges increased by 33. 2% and that of legumes and forbs decreased by 89.9% , 30.7% respectively. The community ecological dominance changed from forbs-dominated to grass-dominated from 2009 to 2011 in removal treatments,and was obviously changed,but it was forbs-dominated during the experiment in control areas. The range of community similarity indices was 0. 7168 - 0.7550 in controls,and 0.6464 - 0. 6732 in removal treatments,and between treatments and controls was 0.5354 -0. 8956. According to the results,we think that disturbance by plateau pikas can decrease the mean heights and coverage of plant community effectively,but the forbs dominated in the plant species
composition, and this not change crucially as a result of disturbance did,thus restoring succession of the plant community would be delayed.

Key words: Degraded grassland, Plant community, Plateau pikas, Restoring succession

摘要: 2009 年4 月至2011 年9 月采用围栏封育和去除法,对去除高原鼠兔的处理组和鼠兔扰动(对照组)区域植物群落结构、物种组成和地上生物量进行了比较分析,旨在阐明高原鼠兔对草地植物群落结构和群落演替的影响。结果表明:去除高原鼠兔处理组和对照区域植物群落平均高度和种盖度逐年上升,均在2011 年达到最大值,平均高度分别为6. 5 cm 和4. 2 cm,二者差异极显著(F =127. 80,df = 1,10,P < 0.01),种盖度分别为126. 5%和117. 9% ,差异不显著;植物群落组成中,处理区域禾草和莎草地上生物量比对照区域分别增加了1 965.1% 和33. 2% ,二者差异极显著(F = 41. 29,df = 1,10,P < 0.001),豆科植物和杂类草分别下降了89. 9% 和30.7% ;处理区域植物群落生态优势度发生了显著变化,由以杂类草为主改变为以禾草为主,而对照组均以杂类草为主,变化不明显。相似性指数2009 - 2011 年在对照区域年间变化范围为0.7168 - 0. 7550,在去除高原鼠兔处理区域年间变化范围为0.6464 - 0. 6732;对照区域和处理区间变化范围为0. 5354 - 0. 8956。根据试验结果我们认为,高原鼠兔的扰动可以有效降低植物群落的平均高度和植物种盖度,但植物种类组成主要以杂类草为主,年间变化不明显,表明鼠兔的扰动延缓了植物群落的恢复演替。

关键词: 高原鼠兔, 退化草地, 植物群落, 恢复演替